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high beam relay - constant buzzing noise
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=86886		 Page 1 of 1
Author:  dunl [ Tue Jul 18, 2017 11:58 am ]
Post subject:  high beam relay - constant buzzing noise
Hi all,

My 2006 CRD that I purchased cheap a while back came to me without a headlight relay (missed checking those, whoops :roll: )
I purchased a relay, put it in, and within 30 seconds it started making a god-awful buzzing noise.

I try to do as much work on my vehicles as possible, but I am convinced that the black magic world of auto-electrical is the devil's hand. Can anyone break it down for my like I'm a 2 year old as to what exactly I would be looking for?

Thanks.
Author:  flash7210 [ Tue Jul 18, 2017 6:49 pm ]
Post subject:  Re: high beam relay - constant buzzing noise
Do your low beams still function normally?
Do you have aftermarket HID headlight bulbs?

A buzzing relay means that the relay is rapidly being switched on and off.
Naturally, it shouldnt do that.

The way it works is pretty simple.
The headlight switch on the column sends a low voltage signal to the ECM (BCM?) which then gounds the relay, turning on the lights.
A rapidy switching relay could mean a bad connection to the relay or a bad switch or a bad module.

However, if you have some sort aftermarket super intense bulbs, they usually require a separate circuit to drive those bulbs. They also create some electrical interference that will cause problems in other circuits.
Author:  Billybob [ Wed Jul 19, 2017 2:25 am ]
Post subject:  Re: high beam relay - constant buzzing noise
Check the fuse for the High Beam...on the panel inside the cabin.

Check what bulbs have bean fitted...if larger wattage bulbs have been fitted then the existing relay may not cope with the existing extra current draw.

When I fitted much larger wattage bulbs I fitted four separate large relays right at the bulbs themselves...one each for left low, left high and same for the RHS. The existing wiring going to the bulbs then activated those relays.

I have since pulled all these relays off as the high power bulbs became illegal here and could no longer be bought.....now use a better quality set of standard Hella bulb.

Any funny electrical problems on the LHD 2006 CRD merits removing the Fuel Filter Head Mounting Bracket as there is a known problem with the wiring harness behind the mounting bracket being forced down on the chassis causing damage to the harness and causing shorting of wires to chassis. :wink:
Author:  dunl [ Wed Jul 19, 2017 2:48 am ]
Post subject:  Re: high beam relay - constant buzzing noise
Thanks for all the tips guys. I'll check on this and post back here if I find the issue. No, there's no HIDs installed, but not sure about the bulbs, as we just bought it a couple of months ago and haven't been using it.

Funny about the bulbs....we bought a second CRD last week, it has super bright bulbs in it, but not apparent resistor wiring that I saw. I'll check that one too.

Thanks again. :BANANA:
Author:  dunl [ Wed Aug 02, 2017 5:18 pm ]
Post subject:  Re: high beam relay - constant buzzing noise
Well, no apprent shorts. I did, however, find a set of 9007 80w bulbs in there, and switched them out for a set of 65w bulbs. I now have high beams.

The buzzing is still there, but I noticed that it onky buzzes if the headlights are Not turned on?
Author:  dunl [ Thu Jun 21, 2018 8:45 pm ]
Post subject:  Re: high beam relay - constant buzzing noise
OK everyone, this vehicle has been sitting for a while, so I am just getting back to this issue. I made sure that the bulbs are the lowest wattage that I can find. I am a novice with the multi meter, so can anyone walk me through how I would try to troubleshoot this issue?

If the buzzing goes away when I turn the lights on, and only buzzes with the daytime driving lights on, then obviously there is continuity from the relay, switch, into the bulbs. I did remove the fuel filter and checked the harness, it's fine.

So how do I track this down? I just finished splicing the rear ABS Hernaez, so this is just one more issue that I want to have finished.

Thanks in advance for any help you can give.
Author:  Billybob [ Fri Jun 22, 2018 12:06 pm ]
Post subject:  Re: high beam relay - constant buzzing noise
I presume you have downloaded the 2006 KJ Service Manual here which has the wiring diagrams?

http://www.colorado4wheel.com/manuals/Jeep/KJ

I however cannot make sense of the page 8W-50-2 which is for the relevant circuitry....and I am a retired Electrical Engineer! This is not too unusual though as there are lots of errors in the wiring diagrams :shock:

Have you swapped out the High Beam and Daylight Running Relays?

I am not too familiar with Daylight Running lights which I assume are only applicable in Canada.
I know it involves fitting a robust relay in the top-left slot on the fuse panel (Junction Block). Does it also require any programming in the BCM? The diagram 8W-50-2 shows the BCM as well as the Multifunction switch are involved in energizing the High Beam Relay. So maybe the BCM programming is wrong or the Multifunction switch may be faulty.

With your meter set to DC volts pull out the High Beam relay and place the leads into female pins 85 and 86. With the headlight High Beam switched ON you expect to see a constant DC voltage of about 12 volts...if the meter reading drastically fluctuates let me know. Now put the meter on DC volts first then AC volts with only Daylight Running Lights On....you should read nothing unless you have a rapidly fluctuating voltage creating a form of AC voltage.

I will read up on how this system is supposed to work and will check up on what BCM functions can be programmed. :wink:
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